1) Field of the Invention
This invention relates to a method for regeneration of an individual coconut (Cocos nucifera) plantlet from cells of an undifferentiated male flower of a coconut tree.
2) Description of the Related Art
Coconut oil is an extremely important oil, which is useful as starting materials in various fields of the industry. Breeding of coconut has been attempted in recent years with a view toward increasing nut production. As a typical example of such breeding, hybridization between a dwarf variety and a tall variety is carried out in order to achieve heterosis. Hybrids resulted from such hybridization are reported to realize an increased yield of oil. Described specifically, breeding is effected (1) by mixed planting selected superior parent trees (mothers and fathers) in an isolated place and then allowing hybridization to occur under natural conditions so as to obtain a hybrid or (2) by artificially hybridizing between selected superior parent trees. However, the method (1) is accompanied by problems that an isolated wide field is essential and the resulting seeds may not exactly be the intended hybrid. The method (2) permits the provision of the intended hybrid without failure, but it is accompanied by a problem that a great deal of labor is required for hybridization and hybrid seeds cannot be obtained promptly in any large quantity.
Reflecting the recent advance in the technology of plant tissue culture, many attempts have been made on various species of plant so as to obtain clone plants having the genetically identical background to original plants. If this technique can be applied for the propagation of a coconut hybrid, many clone plantlets will be obtained promptly and easily from a single tree of elite hybrid having superior characters. This approach can hence be considered to be far superior to conventional propagation methods.
Eeuwens and Blake observed the development of various shoot-like structures upon culture of an undifferentiated male flower tissue of an unmatured inflorescence, and tried to regenerate individual plantlet from such shoot-like structures. They however failed to have the structures grow continuously into individual plantlets.